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Patented July 16, 1935 UNITED STAT-Es AND onto Nicodeiniis, Frankfort-onthe-Main-liochst, 1" f 1 .and Otto WulflgHofheim in Taunus, Germany,

assignorswo L G. Earbenindustrie Aktiengesells cha ft,Frankfort-onsthe-Main, Germany I su ming; Application June 18, 1932',Serial i No. 618,018. In Germany June20, 1931 c I v i ecla ms. (01.260-43 The present invention relates 'topiperidine de-" rivatives and aprocess of preparing the same.

We have found that the sulphonic acids 'of pyridine and its alkylhomologues, particularly the sulphonic acids of pyridine compounds'of Vthe following formulaf wherein one X stands for the group 8031-1 eitherin. the free stateyor *informof a salt, at.

the most two jXfsmay stand for. analkylgroup noble metals, such asplatinum, the metals of the iron group, such as nickel or cobalt,furthermore copper and .theylike. The free sulphonic acids or'the saltsthereof, for instance the readily soluble alkali metal'salts or thesalts of the alkaline-earth metals may be usedin the presence of anindiiferent solvent, for instance water;

In order to accelerate the hydrogenation process it may be advantageousto work at a raised pressure" .and' :a raised temperature, ihowever,

preferably below .150 C. ZFurthermore the re-:

action can be. carried out in .thepreSence ofai solvent'for the pyridinederivative, such as for instance water, alcohol or acetone. V

The following examples serve to illustrate our invention, but they arenot intended to limit it thereto: q i

(1) 181 grams of sodium pyridine -3 -sulphonate are dissolved in 600 cc.of water; 10 grams of nickel precipitated on a porous carrier, areadded. The solution is then stirred in a stirring autoclave whilehydrogen is passed into the autoclave at a pressure of about atmospheresand a temperature of between C. and C. until absorption of hydrogen nolonger occurs. When about 70 liters of hydrogen have been absorbed,thermass is allowed to cool, freed from the catalyst by filteringit bysuction and the filtrate is evaporated to dryness. As a residue thereremains sodium piperidine-3-sulphonate in a nearly purecondition. 7

The reaction occurs in the same manner it between'320 C. and 330 C.without fusing.

BETA-PIPERIDINE SULPHONIG ACIDS v THEIR PRODUCTION other salts are used,for instance the potassium salt'or calcium salt. From the latter there,can

be obtained, by causing it tojreactwith sulphuric If the magnesium saltis used, there obtain'ed directly, after the catalyst has beenseparated, a solution of the free piperidine sulphonic acid. The yieldis nearly quantitative in all cases.

" very well in form of thick, colorless crystals after the aqueoussolution has been concentrated.

The dried acid is decomposed at a temperature of The piperidinesulphonic acid and its salts are readilysoluble in water; They arereadily oxie dized by means of permanganate. The aqueous solution of thefree acid has a neutral reaction.

The compounds show the reactions of secondary readily. l I (2) Thea-DiCOliIlG-B-SlllllhOIllC acid can easily be transformed into thea-pipecoline-e-sulphonic acid or the salts thereof by the same method asdescribedin Example'l. j

The yield is nearly quantitative. The compounds behave completelyanalogous. to the piperidine-sulphonic acid and its salts. V

The free or-pipecoline-pz-sulphonicacid is more readily soluble in waterthan is the piperidine-3- sulphonic acid. It fuses at a temperature ofbetween 315. C. and 320 C. with decomposition.

(3) 20 grams of pyridine-3-sulphonic acid are dissolved in 200 cc. ofwater; a small quantity of platinum oxide is added and the solution istreated with hydrogen in a shaking yessel while gradually raising thetemperature to 50 C. i As soon as the reaction is complete, platinum iseliminated 'byfiltration and the liquid is evaporated untilcrystallization begins. The pipe eridine-sulphonic acid is obtained in agood yield.

piperidine-p-sulphonic acid or its salts.

A good yield is obtained. The substances are colorless and readilysoluble in. water.

formed into the corresponding a-methyl-p'-ethyl- V v catalyst, upon asolutionin an inert solvent of a compound of the followingforn ulafwherein one X stands for the group -SO3H either in the free state or inform of an alkali metal or alkaline earth metal salt, at the most two Xsmay stand for an alkyl group and the remaining Xs stand for hydrogen.

2. The process which comprises hydrogen, in the presence of ahydrogenation catalyst, upon a solution in an inert solvent ofa compoundof theiollowing formula: I 7

whereinone X stands for the group -SO3H either in the free state orinform of analkali metal or alkaline earth metal salt, at the most twoXs may stand for an alkyl group andthe remaining Xs stand for hydrogen,at an elevated temperature not exceeding about 150 C.

3. The process which comprises reacting with hydrogen in the presence ofa hydrogenation catalyst upon an inert solution of a compound of thefollowing formula: V g V;

wherein. X- stands for hydrogenor alkyl and Y stands for the group SOsHeither in the free state or in the form of an alkali metal or alkalineearth metal salt.

4. The process which comprises reacting with reacting with hydrogen inthe presence of a hydrogenation catalyst,'upon an aqueous solution of acompound of the followingformula:

wherein one X stands for the group -SO3H either in the free state-or inform of an alkali metal or alkaline-earth metal salt, at the most two Xs-may stand for an alkyl group and the remaining Xs stand for hydrogen.

' '5. The process which comprises reacting with hydrogen in the presenceof a hydrogenation catalyst upon an aqueous solution of the sodium saltof pyridine-3-sluphonic acid.

6. The process which comprises reacting with hydrogen in the presence ofa hydrogenation catalyst upon an aqueous solution of pyridine-3-sulphonic acid. r

'-7.'-The compounds of the following formula:

1'1 wherein. X stands for hydrogen or alkyl. 8. The 3-sulphonic acid'of'piperidine which is decomposed at'about 320 C. to about 330 C.without melting. f r

9. The compounds of the iollowing formula:

V X: H I

sQ'aY Where Y stands for hydrogen, an alkali'metal, or an alkaline earthmetal, X1 may stand for hydrogen or if X2 is hydrogen, foralkyl, X2 maystand fcrhydrogen or, if X1 andXz are hydrogen, for

alkyl and X: may stand for hydrogen or, if X1 OTTO. ,NICODEMUS.

. QTTOWULEF.

